Preheat oven to 140°C fan. Line baking tray with a silicon mat. Add the sunflowers seeds and pepitas to a food processor, pulse until it becomes a coarse mixture. Be careful not to turn it into a flour.
Transfer to a large mixing bowl.
In a mortar and pestle, grind the coriander seeds to a powder. Add to the mixing bowl. Have a whisk ready.
Add the linseed, sesame seeds, chia seeds, maple syrup, salt and 11⁄2 cups of water.
Whisk straightaway as the chia seeds can clump together if you wait. On a baking tray, using a silicon mat, spread out the mixture so it is roughly 5mm thick. Use a knife to score the mixture into pieces.
We like ours in relatively large squares. Bake for 1 hour or until crispy.